AskBasil
There are various courses but basically they all work on looking at the offender's behaviour and why it is wrong and on looking at the impact on the victims.
Many offenders who have downloaded images of children see it as a victimless crime, that the children photographed are willing and that the images are out there so someone else looking doesn't make a difference.
The course this man possibly went on would look at the victim, at the impact on them and alongside looking at their own (offender) behaviour and also some tactics for not going back to that behaviour.
As some have said you cannot change someone's sexuality but you can educate them about acceptable behaviour.
Back to the OP
There is more to this, a custodial sentence is unusual for a first offence so it may have not been a first offence, or the images were particularly bad. It doesn't say how many of each category does it? Someone with 1000 images where 998 are level 1 would indicate their interest is in level one, but if 998 are level 5 that paints a different picture.